Manufacture of roofing elements



March 10, 1936. SHERMAN MANUFACTURE OF ROOFING ELEMENTS Filed-June I0, 1932 4 sheets-sheep 1 Jizz March 1936- J. c. SHERMAN I MANUFACTURE ROOFING ELEMENTS Filed June 10, T952 4 Sheets-Sheet 2 March 1936- J. c. SHERMAN MANUFACTURE OF ROOFING ELEMENTS 4 She ets-Sheet 5 Filed June 10, 1952 March 10, 1936. c N

MANUFACTURE OF ROOFING ELEMENTS Filed June 10, 1952 4 Sheets-Sheet 4 Patented Mar. 10, 19 36 I UNITED STATES PATENT OFFICE $033,488 MANUFACTURE or aoormo ELEMENTS John C. Sherman, Gotham, Maine, assignor to rown Compan Berlin, N. 11., a corporation 01' Maine Application June 10, 1932, Serial No. 616,393

9 Claims. (Cl. 108-8) This invention relates to the manufacture of One of the faults of roofing elements consistroofing elements whereinto cellulose pulp or ing of a bituminized airlaid web is that such eleequivalent fibrous material, and asphalt or like ments are highly combustible, on account of the binding and waterproofing material, enter as fact that the cellulosic fiber and bitumen emprincipal raw material. ployed as raw materials are highly combustible In making the roofing elements of the present and this combustibility is promoted by the high invention, I prepare what may be termed an airpitch to fiber ratio attained in the airlaid web. laid web of fibers, that is, a web whose fibers This drawback of high oombust y mayain have been deposited from suspension in air or accordance with the present invention, be overm' equivalent gaseous vehicle. Such a web, even come by forming a composite airlaid web by 10 after high compression, is characterized by a initially building p the Web to a Considerable loose and fiufi'y texture, and accordingly a high thickness with cellulose fiber and then depositing absorptivity, which permit the attainment, of a incombustible or mineral fiber, conveniently asv high asphalt to fiber ratio in the finished article, bestos, as a surface layer on the cellulose fiber.

This high asphalt to fiber ratio in the finished One f h rpr in m r s f a mpo w article means high proofness against water and so ade is t a e 1WD ye s f fibe bec me other weathering influence, wherefore there is mOr 0 s e a e W no definite plane little tendency for the roofing element of the of cleavage between the difierent kinds of fiber. present invention to undergo degradation during Ind e i i imp l t segregate or rem v .20 service, for instance, curling and attendant liftcleanly the up fi p a v y thin layer ing by the wind. Important qualities inhere t of asbestos fiber from the basic layer of celluin the bituminized finished article of the present e fi Aceordingly. when a Composite Web invention are its strength, toughness, moulds" mpr nat d w th asp a a u y st u ur ability, flexibility, etc. These are ascribable to of substantial homogeneity throughout s a the loose texture of the airlaid web and the sub- Roofing elements p p from the bituminized, 25 .stantially random arrangement of fiber units Composite Web present a fire-resistant su a e n therein. Rather than being closely interfelted h sense h rk ppe n h r surface and more or less bonded together with a char do not cause their ignition. Wh le it s Pe acteristic lay as in an ordinary sheet of paper p s b t ignite s roofing elements y or roofing felt, the fibers in the airlaid web are renting a strong fla a b w o c fl m 30 merely in loose and random entanglement and against the asbestos fiber-Containing y are relatively free to slide over and part from ertheless this is true of any bituminized roofing. one another. When the airlaid web is impr The main deficiency associated with an allmated with asphalt, the individual fiber units oellulosic fi r as a n eliminated, a y,

'35 become encased in a continuous phase of asphalt, the fire hazard incident-to sparks from a surwhich binds together the fibers tenaciously into r undi fir d ar a s ti a fire when accia finished sheet possessed of the desired ch'ardentally d p d on a roof. e asbestos fiber acteristics hereinbefore mentioned. When such serves a further function, and that is o eo a sheet is subjected to stresses, e. g., tearing tribute mechanical strength to the ash or resi- 40 stresses, these stresses do not become localized, due remaining after complete ombustion of a 40 but are more or less disseminated and dissiroofing element has n ff ted. In other 'pated throughout the entire sheet. In the case Words, the roofing elements c t ini g a sup of ordinary bituminized roofing felt, tearing or ficial layer of asbestos fiber do not tend to libother stress applied locally remains largely conerate sparks When subjected t ng such as fined to the locus of application and may be suf- Will v rise to complete combustion. 45

ficient to cause rupture or tearing apart of con- A most important p e of e p sent inventiguous fibers, since the fibers in the raw felt tion is thatrelating to the fabrication of tapered are tied or bonded together so as not to permit oofi shingles-- Fora 8 yy s, a out of relative displacement. In the finished article standin pr m in the roofing t y as b n of the present invention, however, a stress apthe production f hingles of substantial thick- 50 plied locally cannot be confined to 'a particular ness, especially at the butt edge, and having a locus, since a yielding and relative displacement gradual taper, diminishing from the butt edge to of the fibers can be had in all directions, when the rear or concealed edge, as is true of the usual the proper type of asphaltic impregnant is used wooden shingles. This objective cannot readily ,55 therein. or economically be reached through the use of waterlaid felts, i. e., those prepared on papermaking machines, for papermaking machines are limited as to the thickness of felt which can be properly prepared at their wet ends and/or dried at their dry ends. As a result, the customary bituminized roofing elements of commerce are relatively thin and present a fiat appearance on a roof. Again, their thinness and lack of bulk gives rise to the possibility of high winds raising and sometimes even stripping them from a roof. Various steps have been taken in the direction of overcoming these faults, but these steps were largely in the direction of modifying the superficial aspects of the roofing element, e. g., the asphaltic coating and/or mineral grit deposit, rather than changing the structure of the roofing felt or fibrous foundation itself. In accordance with the present invention, there is no limitation as to the thickness at which the airlaid web may be built up; and, accordingly, I make the web of a thickness consonant with the production of roofing shingles of the desired taper, which taper may be realized either simultaneously with the formation of the web or afterward. There are various ways in which a web of tapering thickness may be prepared in accordance with my invention. Thus, such a web may be made by depositing the fibers from suspension in air into an open-ended chamber defined by a sloping top partition and hence serving to confine the accumulation of fibers thereunder to a sloping bank or.layer. The bottom of such a chamber may be in the form of an endlessly traveling, foraminous carrier, on which the fibers are deposited; and the top partition may also be an endlessly moving, comparatively coarse screen, through which the fiber units can pass on their way to the carrier. The stretch of the carrier defining the bottom of the chamber is preferably under suction, as this promotes the formation of a coherent web. The tapered web thus produced is exceedingly fluffy and weak, and must be compressed in order to withstand a bath of molten asphalt without disintegrating or falling apart. The compression of the web must, of course, be accomplished while retaining the desired taper. When the tapered web is being progressively produced, it is preferable to operate two web-forming machines conjunctively and to effect a uniform compression of the two webs by superposing them with a separator sheet therebetween to form a laminated unit of substantially uniform thickness. When such a unit is progressively passed through press rolls, each tapered web is uniformly compacted throughout while retaining its tapered form. The compressed webs may then be separated and made to pursue an independent course through the rest of the process.

Another way of forming a tapering web of substantially uniform compactness is by initially forming a web of uniform thickness but progressively varying in density from one edge to the other. The latter kind of web may be made either by varying the density of fiber in the shower of fibers delivered to the foraminous carrier and/or by varying the suction under the carrier from one edge to the other. The web of uniform thickness thus made may be led through a pair of press rolls defining a tapered nip and designed to condense the web to a uniform compactness but tapering thickness.

If the web is initially made of uniform thickness and compactness throughout, the desired taper may be imparted thereto by passing it between press rolls defining a predetermined tapered nip.

In such case, the resulting tapered web will be of a non-uniform compactness and will possess the lowest compactness and greatest absorbency at its thick edge portion. Since the thick edge portion is that intended to constitute the butt or exposed portion of 'the finished shingle, it can acquire a higher asphalt to fiber ratio and thus have greater weight and better resistance to weathering action than the thin edge portion; It is, however, preferable to produce a tapered web of uniform compactness throughout and capable of absorbing an optimum proportion of asphalt throughout.

With the foregoing and other features and objects in view, my invention will now be described in greater detail in conjunction with the accompanying drawings, wherein Figure 1 is a side view of the web-forming machine embodying the present invention.

Figure 2 represents a fragmentary transverse section of the machine on the line 2-2 of Figure 1.

Figure 3 is a transverse section through a modified form of machine.

Figure 4 shows in perspective an individual tapered roofing shingle constituting one kind of end product.

Figure 5 illustrates diagrammatically and conventionally two machines arranged conjunctively and designed to produce tapered roofing shingles whose surface portions contain asbestos fiber.

Figure 6 shows schematically the two tapered webs simultaneously proceeding from their respective web-forming machines, with a separator sheet being fed therebetween.

Figure 7 is a transverse section through the webs and separator sheet when they have been brought together for compression.

Figure 8 is a view similar to Figure 7 but after the webs have undergone the action of press rolls.

Figure 9 is an enlarged fragmentary section through the fibrous structure of a composite web.

containing a surface layer of asbestos fibers.

Figure 10 shows schematically a raw, tapered web entering into a punching press adapted to compact it and simultaneously to form a strip shingle.

Figures 11 and 12 are sections on the line ii-H of Figure 10 and respectively show the press in open and in closed position.

Figure 13 shows in perspective a tapered strip shingle constituting another form of end product.

Figure 14 is a diagrammatic and conventional elevation of another form of machine designed for the production of a double-width web of diminishing taper from its longitudinal median line to its edges, said machine including instrumentalities for forming tapered, raw strip shingles on each side of the web.

Figure 15 is a plan view of the machine shown in Figure 14.

Figures 16, 1'7, 18, 19 and 20 are sections taken respectively on the lines l6-l6, lI-ll, I8-I8, Iii-I9, and 2020 of Figure 14.

Referring first to Figure 1 of the drawings, the web-forming machine disclosed therein comprises an endless foraminous carrier I of a character permitting the deposition of fibers thereon, e. g., fibers of the nature of kraft or other chemical wood pulp. The carrier, which may be a wire cloth or screen of, say, to 100 mesh, such as used in a papermaking machine, passes over terminal rolls 2, either one of which may be suitably driven so as to propel the carrier. The

carrier passes over a suction box 3, the edges of the carrier making nice sliding contact with the upper edges of the box, as shown in Figure 2. As the carrier moves over the suction box, it receives a shower of dry fibers coming from an inclined cylindrical container 4 stationed above the suction box. The fibers are permitted to accumulate on the carrier as a layer of tapering thickness in an open-ended chamber whose bottom partition is the carrier itself, whose top partition is an endless wire screen 5 arranged at an angle of inclination to the carrier and sub- -tantially contacting with it at one edge but gradually approaching a distance of maximum separation at' the other edge, and which has a side partition 6 located between the carrier 1 and the wire screen 5 at their edges of maximum separation. The wire screen 5 is shown moving under the container 4 so as to constitute the bottom thereof. It is guided in its movement by four inclined guide rolls I, two of which are shown located on each side of the container near its exit end and the other two of which are shown in a position above the container. All the four rolls 1 may be mounted for rotation in suitable spaced frames 8 extending upwardly from the base frame 9, but only one of the rolls need be rotated so as to cause a propulsion of the wire screen 5. As illustrated, the rear end roll 2 for the carrier I is provided with a pulley III, which derives its motion from a source of power (not shown) through a belt ll. Afiixed to one end of the driven roll 2 may be a bevel gear l2 in mesh with a similar gear l3 on one end of a shaft M, which transmits rotation to the lower rear roll 7 through a bevel gear I5 fixed at its other end and meshing with a similar gear I6 on one end of the roll 1. Any other suitable means for propelling the carrier I and the wire screen 5 may be employed.

The chemical wood pulp or equivalent fibrous material is fedinto the container 4 in properly conditioned dry form. Preferably, the fiber is in a loose and non-clumpy condition, such as-is produced by a hammer mill, shredder, picker, or other machine capable of breaking 'up wood pulp and individualizing the fibers. In order to avoid clogging of the wire screen 5, as well as to break up such fiber clumps as may exist in the pulp fed into the container 4, it is desirable to agitate the supply of fiber kept in the container 4. To thisend, I have shown a rotary agitator -I'l whose shaft [8 extends axially upwardly through the container and is directly driven by an electric motor I 9 suitably anchored to the frame 8. The agitator proper may consist of a. series of bars 20 arranged at spaced intervals on an arm 2! occupying almost the full diameter of the container and aflixed to the shaft l 8, which itself may terminate with a spiral blade 22 operating in close proximity to the wire screen 5. The wire screen 5 must permit the fiber units to fall freely therethrough and hence has openings of size comparatively large, preferably not exceeding about 12 to 14 mesh.

The carrier l is caused to move at a speed such that the layer of fibers deposited thereon will have the full tapered formation bounded by the wire screen 5 as it emerges from the forward end of the fiber-depositing chamber. The tenacity of the layer is determined by the intensity of suction maintained in the suction box 3, as well as upon such other factors as the kind of the fiber used as a raw material. In any event, however, the fiber deposit is exceedingly loose tapered form of the web, and preferably also under conditions to ensure uniform density or compactness therein.

Rather than initially preparing a tapered web, I may deposit on the carrier l a web of uniform thickness but progressively varying in density from one edge to the other, as illustrated in Figure 3. The apparatus shown therein is essentially like that already described, excepting that the wire screen 5 moves horizontally in the desired spaced relationship from the carrier I I and under the container 4, which is stationed vertically rather than in an inclined position. In such case, a side partition 8 is preferably provided between the carrier I and the wire screen 5 at both side edges, so as to confine the shower of fibers within the fiber-depositing chamber. The rolls 1 are, of course, mounted horizontally on the frames 8, so as to guide the wire screen 5 in its desired horizontal path above the carrier I. The suction box 3 has a slatted top whose slats 2|0 extend longitudinally of the machine and which are so dimensioned and spaced as to conduce to a progressively decreasing suction on the carrier from one edge to the other. This means that fibers coming into the fiber-depositing chamber will swarm to that region of the carrier under maximum suction, and that the density of fiber deposited on the carrier will progressively vary from one edge to the other, even though a deposit of uniform thickness may be had. A web thus formedor deposited must undergo a compression gradually increasing from its edge of minimum compactness to its edge of maximum com-.

pactness, in order to acquire a tapered formation of uniform compactness. This result can, as already indicated, be realized by passing the web between a pair of press rolls whose nip is tapered and otherwise dimensioned in proper predetermined relationship with the progressively varying compactness, as well as the thickness of the web initially prepared.

In working with webs initially produced with a tapered formation, it is preferable to effect compacting of two webs simultaneously as they are coming progressively from the web-forming machines, as in such case one may realize a uniform compacting action on both webs by merely passing them between a pair of press rolls, with their surfaces arranged one over the other but separated by a suitable sheet progressively fed therebetween so as to produce a plied unit of substantially uniform thickness, on which the press rolls can act. Such an arrangement of two webforming machines is illustrated in Figure 5, to-- gether with other instrumentalities intended for the production of tapered, individual roofing shingles 220, shown in Figure 4. The two webforming machines shown in Figure 5 are essen.

tially like that shown in Figure 1, one machine, designated generally as 23, being arranged above the other, 24. It is preferable that each web receive a superficial deposit of properly individualized asbestos fibers while it is still in its freshly formed, loose, and fiufiy state. Accordingly, I have shown a hopper 25 arranged to shower the asbestos fibers on each freshly formed web as it issues from its fiber-depositing chamber. The web 26 coming from the upper machine and the web 21 coming from the lower machine are then brought together in superposed relationship with a separator sheet 28 fed in between them, so that a unit 29 of substantially rectangular form, as illustrated in Figures 6 and '7, is built up. In this superposed relation, the webs enter into the nip of a pair of press rolls 30, which serve to compact them uniformly to the desired dimensions and to a condition of tenacity at which they can withstand immersion in a bath of asphalt without disintegration. The compacted webs issuing from the press rolls 30 may then be led away from the separator sheet 28, which makes a circuit over spaced rolls 3|. Each compacted web may be cut crosswise into individual raw shingles 32 by a rotary cutter 33 working cooperatively with a roll 34. The raw shingles may be transferred to a conveyor belt 35 provided with spaced clamps 36 adapted to grip the shingles. The conveyor belt is shown running over a series of guide rolls 31 and carrying the shingles first through a bath of molten asphalt 38 and then through a bath of cold water 39. The molten asphalt enters into a raw shingle to effect a substantially uniform impregnation thereof, whereupon, when the impregnated shingle is dipped into cold water, the asphalt impregnant is congealed to its normally solid condition. The shingle may then be pressed to adjust its dimensions for use or for surfacing with crushed stone or slate. Thus, one surface of the shingle may be warmed sufficiently to render the asphalt plastic, crushed stone or slate sprinkled onto and partially embedded in the plastic asphalt, the excess removed, and the asphalt allowed to congeal.

It is, of course, possible to impregnate the raw, continuous web and to carry out the subsequent steps of the process thereupon, including chilling, pressing, and applying crushed stone or slate, so that completely finished, tapered shingles can be had upon cutting of the finished web. The fibrous structure of each shingle, even when composed of a basic layer of cellulose fiber and a superficial layer of asbestos fiber, is an integral one, for, as depicted in Figure 9, the asbestos fiber tends to become entangled with the cellulose fiber of the freshly formed web and the bonding effect realized thereby is enhanced greatly by compression. The asphalt-impregnated, compressed fibrous structure does not, therefore, exhibit any tendency to delaminate in service or when subjected to flexing.

If desired, tapered so-called strip shingles may be made in accordance with the principles of my invention. The typical strip shingle 4! shown in Figure 13 has a number of shingle-simulating tabs 42 defined by slots 43 extending inwardly from. its thick or butt edge. Such a shingle may be made as shown in Figure 10, by leading a ta pered web 44 as it comes from the web-forming machine into a punching press whose movable head 45 has a face inclined in the same direction as the upper face of the web 44 and provided with a series of sharp-edged blocks 46 projecting downwardly therefrom and designed to punch the slots 43 through the web at its thick edge portion. The platen 4'! of the press is provided with openings 48 extending downwardly therethrough and with which the punching blocks 45 register, wherefore when the head 45 is brought down to compress the web to the desired compactness and taper, as illustrated in Figure 12, shingle-simulating tabs are formed at the thick or butt edge portion. Strip shingles H of the desired length may then be cut crosswise of the compacted, slotted web, then impregnated with asphalt, and otherwise processed in the same manner as individual shingles.

Multiple width webs serving as the base for a number of shingles crosswise thereof may be prepared in accordance with my invention. A double-width web, that is, one capable of yielding two tapered shingles in its crosswise direction, may be prepared as illustrated in Figure 14. As shown therein, an endless, foraminous carrier 5| travels over a suction box 52 stationed near the rear roll of a pair of terminal rolls 53, about which the carrier passes. Arranged in back of the rear terminal roll is a hopper 54 having a rotary gate or valve 55 through which regulated quantities of dry pulp are fed into a chamber 56 at whose closed rear end is a fan or blower 51. The pulp is in such condition, e. g., as delivered from a hammer mill, that upon entering the chamber the individual fibers are suspended in a blast of air and swept through the open forward end of the chamber, onto the carrier 5| and under a pair of endless belts 58 which are arranged side by side and each of which runs at an angle of inclination to the carrier so as to define a clearance space of generally triangular cross-section, as best shown in Figure 16. The belts not only obstruct upward swirling of the fibers, but define the shape of the fiber deposit effected on the carrier to one of generally triangular cross-section,

with the crest of the deposit coinciding substantially with the longitudinal median line thereof. Suitable baiiles 59 may be arranged at the outer edges of the belts 58 and the edges of the carrier 5!, in order to keep substantially all the fibers on the carrier. The web of fibers thus deposited on the carrier may be compacted and cut on its longitudinal median line into two tapered webs, which may then be cut crosswise into individual raw shingles, as hereinbefore described. As shown, however, the web emerging from between the carrier 5| and the belts 58 undergoes the action of press rolls and is then-cut into raw strip shingles Each tapered zone or longitudinal section of the web can be subjected to compression, as by passing into a tapered nip defined by a base roll 60 supporting the full width of the web and a press roll 6| acting upon each section. The compressed web may then pass under a rotary cutter 63 cooperating with a base roll 64 to cut a succession of slots 65 extending transversely within the edges of the web and spaced so that when the web is slit on its longitudinal median line, a strip having shingle-simulating tabs 66 is formed on each side of the web. Such slitting ls shown as being effected by a rotary knife 6'! while the web is being supported on a roll 68. Each strip can be cut transversely into strip shingles of the desired length by a rotary cross-cutter T0 coacting with a base roll I I. The raw strip shingles thus produced may then be impregnated with asphalt and otherwise treated as hereinbefore described. Rather than producing raw strip shingles, however, the raw, continuous web may be impregnated with asphalt and further treated, if desired, to produce a sheet from which finished strip shingles may be progressively out. The con.- tinuous web may, of course, be of a width and cross-section allowing more than two shingles to be obtained crosswise thereof.

In actual practice, I may produce, let us say, tapered individual shingles of a length of 12 inches and a width of 8% inches. The freshly formed web may have a width corresponding to the length of such a shingle, when only a single shingle is cut crosswise thereof. As initially deposited, the tapered web may have a thickness of 3 inches at one edge and inch at the other edge, and weigh 4 ounces per shingle area. If surfaced with asbestos fiber, the weight may be increased to 6 ounces per shingle area. After uniform compression under a pressure of, say, about pounds per square inch, the thick edge is reduced to inch and the thin edge is correspondingly reduced. The compactness of the compressed web is, however, still vastly lower than that of a waterlaid web or paper felt. Upon immersion in molten asphalt, the compressed web absorbs about 26 ounces of asphalt per shingle area or about 430% of its own weight in asphalt. A finished shingle surfaced with asbestos fiber thus weighs about 32 ounces, which weight may be increased to about 35 ounces if crushed stone or slate is embedded in its surface.

The asphalt used as an impregnant is prefererably one which is neither too soft nor too hard under atmospheric temperature. In other words, the asphalt should notfiow or yield easily under pressure, since such asphalt would render the finished shingle liable to damage upon impact or other deforming stresses. On the other hand, a hard asphalt does not impart the optimum toughness, tear resistance, or other qualities desired in the tapered shingle. A typical asphalt suitable as an impregnant was found to be one having the following characteristics:

Melting point (ball and ring test) 149 F. Penetration at 77 F.

(100 gr. 5 sec.) Viscosity at 220 C.

(Stormer viscosimeter) 32 centipoises Ductility at 77 C 12 centimeters ture therefrom and thus to promote the rate at which asphalt is imbibed thereby. The entrance of the hot, molten asphalt into the web may be accompanied by some swelling, wherefore, after the impregnated web has been chilled, as by the action of cold water, it may be pressed to the desired final thickness. While ordinary chemical wood pulps, such as kraft and sulphite, in

bleached or unbleached condition, may be used in preparing the web, a refined wood pulp of high alpha cellulose content comports with the best qualities in the finished article, owing to the stability, softness, and high absorbency of such pulp.

I claim:

1." As an article of manufacture, a roofing shingle comprising an asphalt-impregnated base of compressed, random, airlaid fibers lacking in any characteristic fiber lay and tapering in thickness from its butt to its opposite edge, the asphalt content of said shingle progressively increasing toward its thickest edge but said shingle being of substantially uniform weather-resisting qualities throughout.

2. As an article of manufacture, a roofing shingle comprising an asphalt-impregnated base of compressed, random, airlaid fibers lacking in any characteristic fiber lay and tapering in thickness from its butt to its opposite edge, but of substantially uniform density and weather-resisting qualities throughout.

3. As an article of manufacture, a roofing shingle comprising an asphalt-impregnated base of compressed, random, airlaid fibers lacking in any characteristic fiber lay and tapering in thickness from its butt to its opposite edge and carrying more than 300% of its own weight of asphalt as an impregnant, the asphalt content of said shingle progressively increasing toward its thickest edge but said shingle being of substantially uniform weather-resisting qualities throughout.

4. A method which comprises depositing dry fibers from suspension in air as a web of tapering thickness, compressing said web substantially uniformly throughout while maintaining a tapering thickness therein, cutting said compressed web into tapered roofing shingles, and impregnating said shingles with asphalt.

5. A method which comprises depositing successively dry cellulose fibers and dry asbestos fibers from suspension in air as a composite web of tapering thickness, compressing said web substantially uniformly throughout while maintaining a tapering thickness therein, cutting said compressed web into tapered roofing shingles, and impregnating said shingles with asphalt.

6. A method which comprises forming from dry fiber two webs of tapering thickness, superposing said webs with a separator sheet therebetween to build up a unit of substantially uniform thickness, compressing said unit to compact said webs substantially uniformly throughout, separating said compressed webs from each other, and impregnating each compressed web with asphalt.

7. As a new article of manufacture, a compressed airlaid web of fibers lacking in any characteristic fiber lay and tapering in thickness from one edge to an opposite edge and impregnated throughout with binding and waterproofing material, the impregnant content of said web progressively increasing toward its thickest edge but said web being of substantially uniform weather-resisting qualities throughout.

8. As a new article of manufacture, a compressed airlaid web of fibers lacking in any characteristic fiber lay and tapering in thickness from one edge to an opposite edge and impregnated throughout with binding and water-proofing material, the impregnant content of said web progressively increasing toward its thickest edge but said web being of substantially uniform weatherresisting qualities throughout and said web of fibers comprising a surface portion of incombustible mineral fibers and an under portion of combustible fibers.

9. As an article of manufacture, a roofing shingle comprising an asphalt-impregnated, composite base of compressed, random, airlaid fibers lacking in any characteristic fiber lay and tapering in thickness from its butt to its opposite edge, the asphalt content of said'shingle progressively increasing toward its butt edge but said shingle being of substantially uniform weather-resisting qualities throughout and said base comprising a surface portion of incombustible mineral fibers and an under portion of combustible fibers.

JOHN C. SHERMAN. 

